What do you guys recommend to seal the head gaskets on a flathead 239? Someone recommend oil based aluminum paint???

Thanks

 

I have good luck with coper coat in the spray can on my flathead

 

Plain old hardware store aluminum spray paint, flatheaders have been using it since the 50's. Before the spray can it was brushed on.

Other similar stuff just costs you more money for the honor of buying advertising hype and a "brand" name.

 

i used permatex aviation gasket sealer on my 54 239 worked great.

 

<i>i used permatex aviation gasket sealer on my 54 239 worked great.</i>

I hope you never have to remove those heads. The aviation sealer is great on head bolts and studs however.

 

Uh, just out of curiosity, why do you even need a sealer? Are you talking about a copper or steel shim type gasket? In my limited experience with flathead head gaskets, they were always the "self-sealing" composition of nearly every other head gasket I've used. Educate me.

 

Good question and thats why I came here. From what I understand, and 286merc confirmed, is that the factory used and aluminum based oil paint to seal the heads during assembly.

My guess would be to seal minor imperfections and possible leaks between the head, gasket and block.

The best part is my '49 Merc 239 has the rotatable valve system that was used in the '51 Ford 239, problem is no one has the rotatable system. And all I wanted to do was replace the one bad valve that finally gave way.

 

Well, maybe Carl will sneak back through and straighten us out. He's the resident vintage tech guru. In the meantime, tell me exactly what year engine you've got and which valve spring you need. I'm not sure if the intake and exhaust are different off the top of my head. I'd be happy to send you a couple good, used originals for what it costs to ship them if you'd like. I've got enough flathead parts and junk around here to have my own damned flea market.

 

I appreciate the offer, there both the same. Unfortunantly, I already installed the new, non-rotatable, valve & system in the truck its now a matter of closing her up.

Its a 1949 Mercury M-47 w/ 239. For some reason the Mercs used newer designs then the fords and there are some differences as i just found out with the valve. They also have a different crankshaft that increases the hp to 110. Its a nightmare ordering parts for the engine becasue everyone carrys everyting for the Ford specs and not the Mercs.

You ever get the feeling these things are designed to take all our free time and money?

I love it!

 

Im back, and here goes with a little flathead lore.

The aluminum paint was found to not only hold the head in place during assembly but minimized sealing problems as the engine was broken in. A flatty, even with iron heads, needs a few retorques during break-in. And since the head bolts go into water and the water passages are very close to the bores a flatty needs all the help it can get. Blown head gaskets are a way of life with that engine.
The paint is considered mandatory with aluminum heads.

I dont know about Canadian blocks but down this way there is absolutely no difference between Ford & Merc internals other than crank & pistons. They both got the rotatable valves in 1951 just as they both got the helical oil pump in late 49. There are several minor changes over the years in the block casting but since they were cast only as a block run and not make specific there is nothing to discern between the marques.
There are many external differences with bolt-ons.

With a flatty, parts have been swapped so many times over the years that unless it is a certified original anything is possible. Dealers and rebuilders often swapped in the new valve train at the first valve job which often was within 25-30K miles.

A factory rebuild or replacement engine would have had all the latest upgrades.

BTW, if it has a 239 it is a 100 HP Ford engine, If it is 255 cubes then it has the Merc crank and pistons and is rated 110 HP in the 49-51 years, 125 after that. I believe I remember some Canadian telling me the early Merc trucks all had the 239 from the factory and around 53 the 255 was installed in the larger series such as the F-600 style (whatever it was called up there)